The present invention is directed generally to novel systems and methods for controlling deposition thickness on substrates, and to optical devices manufactured using such systems and methods.
It is believed that in vapor deposition systems such as ion beam sputtering, magnetron sputtering, diode sputtering, thermal evaporation, electron beam evaporation, pulse laser vaporization and cathodic arc vaporization, atoms or molecules ejected from a target material are directed toward a substrate where they condense to form a film. In most cases, the deposited film shows variation in thickness across the wafer that the user would like to eliminate (for uniform deposition) or control (thickness gradient) to meet the needs of a particular application. It would be beneficial to provide a system that improves control of the deposition thickness distribution over a wafer and from wafer-to-wafer during manufacturing runs.
The present invention is directed to a system and method for controlling a deposition thickness distribution on a substrate. A motor rotates the substrate, and at least one deposition thickness sensor senses the deposition thickness on the rotating substrate at two or more radii on the substrate. At least one actuator varies a shadow of a mask that is disposed over the rotating substrate, and a vapor source deposits material on the rotating substrate. The shadow of the mask on the rotating substrate surface is less than an unmasked surface area on the rotating substrate. A process controller is coupled to the thickness deposition sensor and the at least one actuator. In response to an output of the deposition thickness sensor, the process controller varies the shadow of the mask along a radius of the substrate to control the deposition thickness distribution. The mask xe2x80x9cshadowsxe2x80x9d a portion of the substrate from a vapor flux plume created by the vapor source, thereby modifying the film thickness distribution on the substrate. The invention also includes an optical filter that is created using the disclosed system and method.